NVIDIA Cables | Hot Topics: 400G/800G Interconnect Choices and Key Cabling Considerations
November 11, 2025
As artificial intelligence, high-performance computing, and massive data workloads continue to evolve, the demand for unprecedented network bandwidth within data centers is skyrocketing. 400G and 800G network architectures are rapidly becoming the cornerstone of next-generation infrastructure. In this landscape, selecting the right interconnect solution is paramount for achieving optimal performance, efficiency, and scalability.
Understanding High-Speed Interconnect Options: DAC vs. AOC
When deploying 400G and 800G networks, two primary types of NVIDIA high-speed cables are available: Direct Attach Copper (DAC) and Active Optical Cables (AOC). Each offers distinct advantages suited for different deployment scenarios.
- Direct Attach Copper (DAC): These cables use copper twinsaxial cabling with integrated connectors. They are a cost-effective and low-power solution for short-reach connections, typically within the same rack or between adjacent racks. For 400G/800G applications, DAC is ideal for top-of-rack switching and connecting to nearby servers.
- Active Optical Cables (AOC): AOCs utilize fiber optics with embedded optical transceivers at each end. They are lightweight, immune to electromagnetic interference, and support much longer distances than DACs. This makes AOC the preferred choice for connections that span across different rows or rooms in a data center.
Key Considerations for 400G/800G Cabling Infrastructure
Planning your cabling infrastructure for high-speed networks requires careful attention to several critical factors beyond simply choosing between DAC and AOC.
- Reach and Density: Match the cable type to your distance requirements. DAC is optimal for links under 3 meters, while AOC can easily support links of 30 meters, 50 meters, or more for 400G/800G, allowing for greater layout flexibility.
- Power Consumption and Thermal Management: DAC cables are passive and draw no power, helping to reduce overall energy consumption and heat output. AOCs, being active components, consume a small amount of power, which must be factored into power and cooling plans.
- Signal Integrity and Performance: For 400G/800G data rates, maintaining signal integrity is crucial. High-quality NVIDIA high-speed cables are engineered to minimize signal loss, crosstalk, and bit error rates, ensuring stable and reliable network performance.
- Cable Management and Airflow: The physical size and bend radius of cables impact airflow within racks. AOCs are generally thinner and more flexible than DACs, contributing to better cable management and improved cooling efficiency.
Making the Right Choice for Your Deployment
The decision between DAC and AOC for your 400G/800G infrastructure hinges on a balance of cost, reach, and power requirements. For cost-sensitive, short-reach, high-density applications, DAC is an excellent choice. For longer distances where performance and flexibility are priorities, AOC is the definitive solution.
NVIDIA high-speed cables are designed to meet the rigorous demands of modern AI data centers, providing the reliable, high-bandwidth connectivity needed to power the most complex computational workloads. By understanding the nuances of DAC and AOC technologies, network architects can build a robust and efficient foundation for the future.